Error during an upgrade 'Caused by: KRB5KDC_ERR_C_PRINCIPAL_UNKNOWN (-1765328378): Client not fou (4283985)

Flushing Accounts cache: OK
Flushing Domain Info cache: OK
Flushing Name Service cache: OK
Could not load caches- Authentication failed, error = VAS_ERR_NOT_FOUND: Not found
Caused by: VAS_ERR_KRB5: Failed to obtain credentials. Keytab: , Client: MACHINE@DOMAIN.TLD, Service:krbtgt/DOMAIN.TLD@DOMAIN.TLD, Server: mydomaincontoller.domain.tld
Caused by: KRB5KDC_ERR_C_PRINCIPAL_UNKNOWN (-1765328378): Client not found in Kerberos database

This error is caused by QAS being unable to find the computer object MACHINE in AD on the server mydomaincontoller.domain.tld . This can be because there is a temporary AD or network problem, or because there is actually something wrong with the computer object. Usually, during an upgrade, there is no reason to suspect that the computer object does not exist, or problems would have been apparent earlier.

Flush the caches manually with the command:

/opt/quest/bin/vastool flush

If the flush is successful, then the temporary problem no longer exists.